- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- HISTORY

# NAME

BN_new, BN_init, BN_clear, BN_free, BN_clear_free - allocate and free BIGNUMs

# SYNOPSIS

     #include <openssl/bn.h>

     BIGNUM *BN_new(void);

     void BN_init(BIGNUM *);

     void BN_clear(BIGNUM *a);

     void BN_free(BIGNUM *a);

     void BN_clear_free(BIGNUM *a);

# DESCRIPTION

`BN_new()` allocates and initializes a BIGNUM structure. `BN_init()` initializes an existing uninitialized BIGNUM.

`BN_clear()` is used to destroy sensitive data such as keys when they are no longer needed. It erases the memory used by a and sets it to the value 0.

`BN_free()` frees the components of the BIGNUM, and if it was created by BN_new(), also the structure itself. `BN_clear_free()` additionally overwrites the data before the memory is returned to the system. If a is NULL, nothing is done.

# RETURN VALUES

`BN_new()` returns a pointer to the BIGNUM initialised to the value 0. If the allocation fails, it returns NULL and sets an error code that can be obtained by ERR_get_error.

BN_init(), BN_clear(), `BN_free()` and `BN_clear_free()` have no return values.

# SEE ALSO

bn, ERR_get_error

# HISTORY

BN_new(), BN_clear(), `BN_free()` and `BN_clear_free()` are available in all versions on SSLeay and OpenSSL. `BN_init()` was added in SSLeay 0.9.1b.